The researchers examined the oxygen requirements of a modern and common sea sponge (Halichondria panicea) from Kerteminde Fjord in Denmark and found the sponge could survive and thrive at oxygen levels as low as 0.5 percent to four percent of present atmospheric oxygen levels.

The sponge was selected because the animal’s physiology and anatomy closely resemble the first known and documented animal life that is considered to be the first animal life on Earth.

Prior to this study, animal life was considered to have first arisen on Earth between 542 million years ago and 850 million years ago when oxygen levels had increased to sufficiently high enough levels to support animal life.

The researchers also point to previous studies that indicate oxygen levels rose to the equivalent of present levels at least one time prior to any known development of animal life on Earth.

The research essentially negates the concept that animal life formed due to increased levels of oxygen in Earth’s atmosphere.